Improvement in cut-off gear for steam-engines



' F. DOUGLAS. 1

CUT-OFEGEAR'FOR STEAM-ENGINES.

No. 180,211. Emma July 25,1876.

N'PETERS, FHOYO-UTHOGRAFHER, WASHINGTON D. C.

o STATES FIG- PATE

FRANK DOUGLAS, OF CHICAGO, ILLINOIS.

Specification forming part of Letters Patent No. 180,211, dated July 25,1876; application filed February '2, 1876.

To all whom it may concern:

Be it known that I, FRANK DOUGLAS, of Chicago, State of Illinois, haveinvented certain Improvements in Valve-Gearing for Steam -Engines, ofwhich the following is a specification My invention relates to the classof steamengines known as the automatic cut-off engines, in which theinduction or cut-ott' valves are actuated by the governor in such amanner as to promptly cut off the steam at any point of stroke, thecut-off taking place earlier or later in the stroke, to accommodate thevaried loads on the engine and the varied pressure in the boiler.

The valves, with their connections to the governor-screw, and, byeccentric rods, to the shaft, are very clearly shownin the accompanyingdrawing, Figure 1. The valves and ports are more clearly shown in theplanview,

Fig. 2.

A represents the frame of the engine; B, the shaft; 0, the mainvalve-eccentric; 1), the eccentric --rod 5 E, the valve rod; F, mainvalve, which acts as induction and exhaust valves G, the eccentric thatimparts motion to'the cut-ofivalves; H, the cut-off eccentricrod; Irocking arm,-pivoted at J. Disk K is pivoted on arm I. and has two steelwrist-pins, a a, placed diametrically opposite each other. Rod Lconnects pin a with sleeve valve-stem m, which is locked to cut-offvalve n. Rod O connects pin a with valve-stem P, which stem passesthrough sleeve m, and is locked to cutoff valve n. Screw R is intendedto represent part of the screw of my governor patented September 8,1863. Nut S, which is bolted to the bed of the engine, is also a part ofthe governor. Connection T connects screw R to lever to, pivoted at V,and connection W connects lever to with pin 6 on disk K.

stantially as herein specified.

The efl'ect produced by a change of speed is to run the governor-screw Rup or down, and thereby rotate the disk correspondingly. The rotation ofdisk K on its pivot draws one cutoff valve toward it, and pushes theother the same distance in the opposite direction, the effect of whichis to separate or bring toward each other the cut-oft valves 11. a,cutting the steam ofl' sooner in the stroke when the valves areseparated, and allowing the steam to follow further when they are drawncloser together, thus automatically governing the engine while the steamis admitted to the piston under full boiler-pressure, and a saving ofits full expansive force is maintained.

The governor is so constructed that its belt turns the screw R, andactuates the cut-off valves, while the centrifugal force of thegovernor-balls only indicate how much shall be done, the effect ofWhich'is to give great power and perfect regulation. a 1

The main valve F has two induction-ports through it, marked a9 m, whichadmit steam to the cylinder-ports w as. The exhaust steam passes outthrough main valve F to exhaust chest or port y.- The out off valves a ahave their seat on top or outside of main valve F, and as the motion ofthe main valve by eccentric O is nearly opposite to the motion of cutoffvalves by eccentric G, the cutoff valves rapidly close the port throughvalve F, and

thereby out ofif the steam, as indicated by the governor.

What I claim as my invention is- The combination of valves a a, workingon top of valve B, sleeve m, disk K, on rock-arm I, with lever to, andgov73'r'iTo'r-screw R, sub- FRANK DOUGLAS.

Witnesses:

'THOMAS C. GoNNoLLY,

ULYssEs G. WHITE.

